Novel keto-hydroxy-perinaphthoxazines



United States Patent Office 3,431,260 NOVEL KETO-HYDROXY-PERI- NAPHTHOXAZINES Stanley M. Bloom, Waban, Mass., assignor to Polaroid Corporation, Cambridge, Mass, a corporation of Delaware No Drawing. Original application Dec. 4, 1963, Ser. No. 328,116, now Patent No. 3,320,063, dated May 16, 1967. Divided and this application Jan. 9, 1967, Ser. No. 607,886

US. Cl. 260-244 6 Claims Int. Cl. C07d 87/00; G03c /38 ABSTRACT OF THE DISCLOSURE Novel keto-1,3-peri naphthoxazines useful as silver halide developing agents are prepared by treating amino naphthoquinones with phenyl chlorocarbonate to form phenyl-5-(1,4 naphthoquinonyl) carbamates which are reduced to yield the desired naphthoxazines.

This application is a division of copending application Ser. No. 328,116, filed Dec. 4, 1963, now US. Patent 3,320,063, issued May 16, 196 7.

This invention relates to photography and more particularly to processes and compositions for the development of photosensitive silver halide elements. In one aspect, this invention relates to transfer processes which involve the development of a latent image in an exposed silver halide emulsion and the transfer of components from said emulsion to another layer to effect the formation of a print in said other layer, and to products useful in the performance of said transfer processes.

It has been proposed to carry out transfer process by applying an aqueous solution of a silver halide developing agent to a silver halide stratum and an imagereceptive stratum which are in superposed relation. The developing agent reduces exposed silver halide to silver, said developing agent becoming oxidized in the process. Thereafter, the remaining unoxidized developing agent is transferred in an imagewise distribution to the imagereceptive stratum to form a photographic image.

It is one object of the present invention to provide novel compounds characterized by their ability to develop photographiclatent images with a high degree of discrimination, and processes for preparing such compounds.

A further object is to provide novel processes for the development of silver halide emulsions, in which the developing agent is capable of developing a photographic latent image and imparting a reversed or positive image of said developed image to a superimposed image-receiving element.

A further object is to provide novel processes suitable for use in preparing monochromatic and multichromatic photographic images.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the processes involving the several steps and the relation'and order of one or more of such steps with respect to each of the others, and the products and compositions possessing the features, properties and the relation of elements which are exemplitied in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a=fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description.

It has now been discovered that certain compounds, herein referred to as leuco compounds or as leuco devel oping agents, are effective as discriminating silver halide developing agents, and in addition to developing the ex- 3,431,260 Patented Mar. 4, 1969 wherein R and R are hydrogen or lower alkyl, R R and R are each members from the group consisting of hydrogen, hydroxyl, halogen, lower alkyl, substituted lower alkyl, aryl, and substituted aryl, and X is hydrogen or lower alkyl.

As specific examples of the leuco compounds within the scope of this invention, mention may be made of the following:

ml 6 II 0 2-keto-7-hydroxy-1,3-peri-naphthoxazine 11111 5 \C (l 2-keto-7-hydroxy-8-methyl-1,3-peri-naphthoxazine 2-keto-7-hydroxy-8,9 dimethyl-1,3-peri-naphthoxazine CH3 i 2-keto-6,7-dihydroxy-8,9-dimethyl-1,3-perinaphthoxazine 3 2-keto-7-hydroxy 8-ethyl-l,3-peri-naphthoxazine 2-keto-7-hydroxy-8,9-diethyl-1,3-peri-naphthoxazine 2-keto-7-hydroxy-6,8,9-trimethyl-1,3-peri-naphthoxazine 2-keto-7-hydroxy-6-methyl-8,9=diethyl-1,3-perinaphthoxazine 2-keto-7-hydroxy-4,6,8,9-tetramethyl-1,3 -perinaphthoxazine 2-keto-7-hydroxy-4,6-diethyl-8,9-dimethyl-1,3-perinaphthoxazine 2-keto-7-hydroxy-8,9 dichloroethyl-1,3-perinaphthoxazine 2-keto7-hydroxy-4,6-dichloroethyl-8,9-dimethyl-l,3-perinaphthoxazine 2-keto-6,7-dihydroxy-8,9-dichloroethyl-1,8-perinaphth'oxazine The leuco compounds contemplated herein may be pre pared by the following general procedure:

Initially, nitro naphthoquinones having the general formula:

wherein R and R are hydrogen or lower alkyl, R R and R are each members from the group consisting of hydrogen, halogen, 'hydroxyl, lower alkyl, substituted lower alkyl, aryl, and substituted aryl, are synthesized, either from the corresponding naphthoquinone by nitration as described in US. Patent 2,687,939, to Mario F. Sartori, issued Aug. 31, 1954, or by other known methods, such as those described in U.S.S.R. Patent 108,812, abstracted in Chemical Abstracts, vol. 52, p. 11942i, and in U. U. Vorozhtsov et al., Zhur. Vsesoyuz Khim. Obshchestva im. D. I. Mendeleeve, vol. 5, pp. 474-75. Thereafter, the compounds produced thereby are reduced to the corresponding amino compounds. Satisfactory techniques for this step are also described in US. Patent 2,687,939. Additionally, methods are described therein for the introduction of selected substituents into the naphthalene ring. The resultant compounds are amino naphthoquinones having the general formula:

X-NH 6 wherein R and R are hydrogen or lower alkyl, R R and R are each members from the group consisting of hydrogen, halogen, hydroxyl, lower alkyl, substituted lower alkyl, aryl, and substituted aryl, and X is hydrogen or lower alkyl; they provide the starting materials for the novel synthesis described below. It will be understood that any commercially available substituted or unsubstituted naphthoquinone can be treated as described above and reduced to ultimately produce a keto-perinaphthoxazine which is similarly substituted.

The amino naphthoquinones are treated with phenyl chlorocarbonate in a non-aqueous solvent to form phenyl- 5-( 1,4-naphthoquinonyl)-carbamates having the general formula:

wherein R represents R and R in Formula 1, R represents R R and R in Formula 1, and X is hydrogen or lower alkyl, Thereafter, the resulting phenyl-5-(l,4- naphthoquinonyl)-carbarnates may be treated with a reducing agent in an aqueous alkaline solution to form the desired 2-keto-7-hydroxy-1,B-peri-naphthoxazines. Suitable reducing agents are those which will reduce the quinone moiety to hydroquinone, such as alkali metal dithionites, alkali metal borohydrides, and zinc in alkaline solution. The solution should have a pH of at least about 9 and for this purpose, a weak base, such as sodium carbonate or ammonia should be employed. Moreover, it may be advantageous to deaerate the solution throughout the course of the reaction in the interest of inhibiting oxidation of the products.

In both of the above steps, i.e., the carbamate formation and subsequent reduction, the relative proportions of reactants are not critical; however, it is advantageous to have present an excess of the reactants, i.e., phenyl chlorocarbonate and reducing agent, in order to insure good yields of the desired materials.

The following are examples of the procedure for making compounds as described herein, and are presented by way of illustration only:

Example 1.-2-keto-7-hydroxy-8,9-dimethyl- 1,3 -peri-naphthoxazine (A) Preparation of phenyl-5-(2,3-dimethyl-l,4-naphthoquinonyl)-carbamate.4.5 grams (0.22 mole) of 5- amino-2,3-dimethyl-1,4-naphthoquinone were dissolved in 500 ml. of dry toluene containing 2.4 grams (0.03 mole) of dry pyridine. To the above solution, 7.0 grams (0.044 mole) of phenyl chlorocarbonate were gradually added over a period of /2 hour. Thereafter, the solution was refluxed for two hours. Following concentration of the solution and the addition of hexane, 5 grams of a yellow precipitate were recovered, said yellow precipitate melting at -195 C. The material was recrystallized from toluene, and the product obtained therefrom melted at 199-200 C. and was found upon analysis to be phenyl-5- (2,3 dimethyl-1,4-naphthoquinonyl)-carbamate, having the formula Calc. for C H O N: C, 71.03; H, 4.71; N, 4.36. Found: C, 70.72; H, 4.60; N, 4.30.

(B) Preparation of 2-keto-7-hydroxy-8,9-dimethyl-1,3- peri-naphthoxazine.-12 grams of phenyl-5-(2,3-di methyl-l,4-naphthoquinonyl)-carbamate prepared by the method of Step A above were powdered and added to a deaerated mixture of 350 ml. of ethanol and 250 ml. of Water. 24 grams of sodium carbonate were added, care being taken to keep the reaction medium flushed with nitrogen. After dissolution of the sodium carbonate, 12 grams of sodium dithionite was added and the reaction lib-Ill 6 Calc. for C H O I: N, 6.1. Found: N, 6.0; 6.1.

The following is an example of the use of the novel compounds described herein as silver halide developing agents in accordance with this invention, and is given as illustration only:

Example 2 An image-receiving element was prepared by coating a subcoated baryta paper with a partial butyl ester of poly- (ethylene/maleic anhydride), followed by a layer of polyvinyl alcohol and a layer of a mixture of polyvinyl alcohol and poly-4-vinylpyridine. A detailed description of the process for preparing such image-receiving elements may be found in the copending U.S. patent application of Edwin H. Land, Ser. No. 234,864, filed Nov. 1, 1962.

A photosensitive element for use with the above imagereceiving element was prepared by coating a silveriodobromide emulsion (of the type used in Type 42 Polaroid Land Picture Rolls) with an acetone solution comprising 2% cellulose acetate hydrogen phthalate and 2.1% of a keto hydroxy-peri-naphthoxazine having the formula:

CH3 a C/ II 0 as prepared in Example 1 above, and drying the coating.

The photosensitive element was exposed to a test object which was designed to completely expose a portion of the element and to leave the remaining portion totally unexposed. An aqueous liquid processing composition comwas then spread in a layer approximately 0.0026" thick between the photosensitive element and the image-receiving element as said elements were brought into superposed relationship. After an imbibition period of approximately one minute, the image-receiving element was separated. Thereafter, the maximum densities in the exposed and unexposed portions of the developed negative Were determined by means of an I R Densichron. The density measurement for the exposed portion was 0.58; for the unexposed portion, 0.18, thereby indicating the utility of the keto-hydroxy-peri-naphthoxazine as a discriminating developing agent.

The success with which the keto-hydroxy-peri-naphthoxazines described herein can be used as developing agents is especially surprising and unexpected in view of the fact that similar analogous compounds, such as naphthohydroquinones,

wherein R and R represent a variety of substituents such as those described above, 5 amino 1,4 naphthohydroquinones,

and keto hydroxy-peri-anthroxazines,

are markedly less effective, as illustrated by the following examples:

Example 3 The process described in Example 2 was followed, except that an aminonaphthohydroquinone having the formula:

OH CH. CH

Hrl l (5H was substituted for the keto-hydroxy-peri-naphthoxazine. The developed negative showed a D of 0.25 and a D of 0.16.

Example 4 The process described in Example 2 was followed, except that a keto-hydroxy-peri-anthroxazine having the formula:

was substituted for the keto-hydroxy-peri-naphthoxazine. The final developed negative was similar to that obtained in Example 3, in that there was relatively little difference in density between the exposed and unexposed portions.

The leuco developing agents described herein are substantially colorless or only faintly colored, but upon oxidation, assume various colors depending upon the nature of the groups substituted thereon. Specifically, referring to Formula 1, the substituents R R and R can be selected to determine the final color of the oxidized developing agent, R having the most pronounced effect. Accordingly, it is possible to predetermine a given desired hue in the final image by appropriate selection of substituents.

The color-forming ability of the developing agents described herein renders them suitable for the formation of colored images in photographic products and processes of the type described, for example, in US. Letters Patent Nos. 2,647,049, 2,698,244, 2,909,430, and 2,968,554. In these patents, examples of diffusion transfer reversal processes are disclosed wherein a photographic material, such as a photosensitive element comprising an exposed silver halide emulsion layer containing a latent image, is processed to impart to an image-carrying or image-receiving element a reversed or positive dye image of said latent image by permeating into said emulsion layer a suitable liquid processing composition and bringing said photosensitive element into superposed relationship with an appropriate image-receiving element.

In using the keto-peri-naphthoxazines in the above procedures, a photosensitive element comprising a silver halide emulsion is exposed and a liquid processing composition applied thereto, as by immersing, coating, spraying, flowing, etc., in the dark. In a preferred embodiment, the photosensitive element contains a layer of one of the above leuco compounds, and the liquid processing composition is applied to the exposed photosensitive element in a uniform layer as this element is brought into superoq 'JIIQLUQIQ fiurxgooai-ofietur ma q pn drqsnope ol pesod liquid processing composition permeates the emulsion and provides a solution of leuco compound substantially uniformly distributed therein. As the latent image is developed, the leuco compound is oxidized and immobilized in exposed areas. This immobilization is apparently primarily due to a change in the solubility characteristics of the leuco compound upon oxidation, and especially as regards its solubility in alkaline solution. The unoxidized leuco compound retains its solubility in the liquid processing composition, thereby providing an imagewise distribution of unoxidized leuco compound, at least a part of which is transferred, by imbibition, to a superposed imagereceiving element. The latter element receives a depthwise diffusion, from the emulsion, of unoxidized leuco compound without appreciably disturbing its imagewise distribution, thereby giving a reversed, or positive, colored image of the developed negative image. The image-receiving element may contain agents adapted to oxidize, mordant, or otherwise fix the diffused, unoxidized leuco compound. Imbibition periods of approximately one minute have been found to give good results, but this contact period may be adjusted where necessary to compensate for variation in temperature or other conditions. The desired positive image is revealed by stripping the imagereceiving element from the photosensitive element at the end of the imbibition period.

The leuco compounds disclosed herein may be disposed in the liquid processing composition in the imagereceiving element or in the photosensitive element, for example, in, on, or behind the silver halide emulsion layer. When employed in either element the leuco compound becomes solubilized by the liquid processing composition as it permeates the element. In a preferred embodiment, a coating or layer of the leuco compound is incorporated in the photosensitive element, preferably behind the silver halide layer, i.e., on the side of the emulsion adapted to be located most distant from the,

photographed subject when the photosensitive element is exposed. Placing the leuco compound behind the emulsion layer has the advantage of providing increased contrast in the positive image, and also minimizesany light-filtering action by the leuco compound. If the leuco compound is colorless or otherwise non-absorptive of light complementary in color to the sensitivity of the emulsion, it may be incorporated in the silver halide emulsion without adverse light-filtering effects.

Where the leuco compound is employed in a layer within the photosensitive element, it may be applied by using coating solutions containing about 0.5 to 8%, by weight, of the leuco compound. Similar concentrations may be used if the leuco compound is utilized as a component of the liquid processing composition. A particularly useful method of incorporating the leuco compound is to dissolve it in a water-immiscible solvent, disperse the resulting solution in gelatin, and apply the resulting dispersion to provide the layer of leuco compound.

The liquid processing composition referred to above comprises at least an aqueous solution of an alkaline material, such as diethylamine, sodium hydroxide, potassium hydroxide, or sodium carbonate. If the liquid processing composition is to be applied to the emulsion by being spread thereon, preferably in a relatively thin, uniform layer, it may also include a viscosity-increasing compound constituting film-forming material of the type which, when spread over a Water-absorbent base, will form a relatively firm and relatively stable film. A preferred film-forming material is a high molecular weight polymer such as a polymeric water-soluble ether which is inert to an alkaline solution, as, for example, a hydroxyethyl cellulose or sodium carboxymethyl cellulose. Other film forming material or thickening agents may be employed whose ability to increase viscosity is substantially unaffected when left in solution for a long period of time.

The unoxidized leuco compound which diffuses to the image-receiving element is oxidized to provide the desired positive dye image. This oxidation may be effected by merely exposing the stripped image-receiving element to the air. In a preferred embodiment, the image-receiving element has incorporated therein an oxidizing agent for the purpose of speeding up dye formation and providing full image density immediately upon stripping. The incorporation of an oxidizing agent in the image-receiving element for the purpose of oxidizing unreacted developing agent permeated therein is described in US. Patent No. 2,559,643. As examples of suitable oxidizing agents, mention may be made of peroxy compounds such as sodium or potassium perborate, certain dichromates such as ammonium dichromate, and compounds having polyvalent metallic elements in higher valent form such as copper, iron, and cerium, wherein the metallic element is in a higher valent form. Examples of these latter-mentioned agents are cupric salts, such as cupric sulfate Another suitable oxidizing agent is benzoyl peroxide. Other useful oxidizing agents are quinones, and particularly, 2,3-dicyano-1,4-benzoquinone.

The following non-limiting example illustrates the use of the keto-peri-naphthoxazines described herein as leuco dyes in the formation of colored images.

Example 5 An image-receiving element was prepared by coating a 2:1 mixture, by weight, of polyvinyl alcohol and poly- 4-vinylpyridine on a cellulose acetate-subcoated baryta paper.

A photosensitive element for use with the above imagereceiving element similar to that in Example' 2, and containing the same keto-peri-naphthoxazine, was prepared.

The photosensitive element was exposed to a test object which was designed to completely expose a portion of the element and to leave the remaining portion totally min-gton 99, Del., under the trade name Natrasol 250] 4.03 Sodium thiosulfate 1.15 Benzotriazole 2.3 N-benzyl-a-picolinium bromide 2.3

was then spread in a layer approximately 0.0026" thick between the photosensitive element and the image-receiving element as said elements were brought into superposed relationship. After an imbibition period of approximately one minute, the image-receiving element was separated and examined. An image was observed which was salmon pink in color, the density of which increased after exposure to air.

It will be apparent that by appropriate selection of the image-receiving element from among suitable known opaque and transparent materials, it is possible to obtain either a colored positive reflection print or a colored positive transparency. Likewise, the inventive concepts herein set forth are adaptable for multicolor work by the use of special photographic materials, for example, screen type negatives or film materials of the type containing two or more photosensitized elements associated with a suitable number of image-receiving elements and adapted to be treated with one or more liquid processing compositions, appropriate developing agents suitable to impart the desired subtractive colors being incorporated in the photosensitive elements or in the liquid processing composition. Examples of such photographic materials are disclosed in the previously mentioned patents.

In the preceding portions of the specification, the expression color has been frequently used. This expression is intended to include the use of a plurality of colors to obtain black.

It should be noted that the leuco developing agents of this invention provide the desired colored image upon oxidation and do not depend upon or require coupling reactions to produce the desired color. They thus provide a complete departure from photographic color processes in which the color is produced by a coupling reaction involving the oxidized developing agent.

It will be noted that a conventional silver halide developing agent may be incorporated with the leuco compounds described herein. This conventional developing agent is preferably used in a quantity suflicient to accelerate development of the latent image. Use of such a developing agent has been found helpful in improving the tonal range or steps in the positive image. Some of the unreacted leuco compound may be oxidized by an energy transfer reaction with oxidized auxiliary developing agent. Among the developing agents suitable for this purpose are p-N-benzylamino-phenol, ascorbic acid, p-anilinophenol, 1-amino-2-naphtho1, diethylhydroxylamine, and Metol (p-N-methyl-amino-phenol) In employing the leuco compounds of this invention in film units suitable for use in self-developing cameras, such as the Polaroid Land camera, sold by Polaroid Corporation, Cambridge, Massachusetts, the film unit may comprise a photosensitive element, an image-receiving element adapted to be superposed on said photosensitive element, and a rupturable container holding a processing composition and adapted to release its contents for spreading over predetermined areas of said elements after rupture. Suitable'structures of this type are described in the herein-mentioned US. patents. The leuco compound may be located in the processing composition or in a layer of the photosensitive element.

The developing agents of this invention may be used also in conventional photographic processes, such as tray or tank development of conventional photosensitive films, plates, or papers to obtain monochromatic or toned prints or negatives. By way of example, a developer composition suitable for such use may comprise an aqueous solution of approximately 12% of the leuco compound, 1% sodium hydroxide, 2% sodium sulfite, and 0.5% potassium bromide. After development is completed, any unreacted leuco compound is washed out of the photosensitive element, preferably with an alkaline washing medium or other medium in which the oxidized leuco compound is soluble. The expression toned is used to designate photographic images wherein the silver is retained with the resultant dye, whereas monochromatic is intended to designate dye images free of silver.

Since certain changes may be made in the above products, compositions, and processes without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A keto-hydroxy-peri-naphthoxazines having the formula:

wherein R and R are each members selected from the group consisting of hydrogen and lower alkyl, R R and R are each members selected from the group consisting of hydrogen, hydroxyl, halogen, lower alkyl, halo lower alkyl, and X is a member selected from the group consisting of hydrogen and lower alkyl.

2. 2-keto-7-hydroxy-1,3-peri-naphthoxazine.

3. 2-keto-7-hydroxy 8,9 dimethyl-1,3-peri-naphthoxazme.

4. 2-keto-6,7-dihydroxy-8,9-dimethyl-1,3-peri-naphthoxazme.

5. The method of preparing compounds as defined in claim 1 comprising treating an aminonaphthoquinone having the formula:

.X-NH I wherein R and R are each members selected from the group consisting of hydrogen and lower alkyl, R R and R are each members selected from the group con sisting of hydrogen, hydroxyl, halogen, lower alkyl, halo lower alkyl, and X is a member selected from the group consisting of hydrogen and lower alkyl, with phenyl chlorocarbonate in a non-aqueous medium and treating the product obtained thereby with a reducing agent in an aqueous alkaline solution to form the desired product.

6. The method of preparing compounds as defined in claim 1 comprising dissolving an aminonaphthoquinone having the formula:

wherein R and R are each members selected from the group consisting of hydrogen and lower alkyl, R R and R are each members selected from the group consisting of hydrogen, hydroxyl, halogen, lower alkyl, halo lower alkyl, and X is a member selected from the group consisting of hydrogen and lower alkyl, in a non aqueous solvent, adding an excess of phenyl chlorocarbonate to the solution thereformed, refluxing the reaction mixture formed thereby to form phenyl-5 (1,4-naphthoquinonyl)- carbamate, dispersing said phenyl-5-(1,4-naphthoquinonyl)-carbamate in an aqueous solvent, adding sodium carbonate and sodium dithionite to the dispersion thereformed, refluxing the reaction mixture, acidifying said mixture, and precipitating the desired product.

References Cited UNITED STATES PATENTS 3,296,259 1/1967 Strube 260244 HENRY R. JlILES, Primary Examiner.

R. T. BOND, Assistant Examiner.

US. Cl. X.R. 965 1, 59, 61 

